Get presence of a channel

//native

type Ably = {

  apiKey: string;

};

/**

 * Get presence of a channel

 * Get presence on a channel

 */

export async function main(

  auth: Ably,

  channel_id: string,

  format: "json" | "jsonp" | "msgpack" | "html" | undefined,

  clientId: string | undefined,

  connectionId: string | undefined,

  limit: string | undefined,

  X_Ably_Version: string,

) {

  const url = new URL(`https://rest.ably.io/channels/${channel_id}/presence`);

  for (const [k, v] of [

    ["format", format],

    ["clientId", clientId],

    ["connectionId", connectionId],

    ["limit", limit],

  ]) {

    if (v !== undefined && v !== "" && k !== undefined) {

      url.searchParams.append(k, v);

    }

  }

  const response = await fetch(url, {

    method: "GET",

    headers: {

      "X-Ably-Version": X_Ably_Version,

      Authorization: "Bearer " + auth.apiKey,

    },

    body: undefined,

  });

  if (!response.ok) {

    const text = await response.text();

    throw new Error(`${response.status} ${text}`);

  }

  return await response.json();

}